Centerless grinding machine



May '14, 1957 E. L. HORTON 2,791,870

CENTERLESS GRINDING MACHINE Filed Oct. 19, 19 53- I 20 Z7 /5 .I

. f /A H IIENTOR an al on. 7 BY y l3 AUOQNEYS United States PatentCENTERLESS GRINDING MACHINE Earl L. Horton, Saginaw, Mich., assignor toS. & E.

Machine Products, Inc., Bridgeport, Mich., a corporation of MichiganApplication October 19, 1953, Serial No. 386,760

3 Claims. (Cl. 51-103) This invention relates to grinding apparatus andmore particularly to a centerless grinding attachment for conventionalexternal grinding machines.

One of the prime objects of my invention is to provide a practical andeffective centerless grinding attachment for external grinding machineswhich will substantially broaden the field of use of such machines.

A further object of the invention is to design a highly efficient andreliable centerless grinding attachment of simple construction which canbe economically manufactured and mounted on conventional externalgrinding machines of all kinds without necessitating extensivechangeovers or adaptations.

patented May 14, 1957 12, which may be an emery wheel or the like,removably mounted on an arbor 13 as shown, the one end of the arborbeing reduced and threaded as at 14 to accommodate a nut 15 which clampsthe wheel 12 between the washer 16 and the shoulder 17 formed byreducing the 'arbor 13. The ends of the arbor 13 are bored with taperedopenings as at 18 to accommodate the head and tail stock centers 19 and20 respectively with which most external grinding machines are commonlyprovided, and

. a dog 21 is clamped to the head end of the arbor 13 to accommodate alug 22 projecting from the drive spindle of the machine which alsosupports the center 19 and is mounted in the head stock (not shown) ofthe machine.

The center 19, of course, is a so-called live center and I the center 20a dead center, and the spindle is driven Another object of the inventionis to design a centerless grinding attachment of the type describedwhich is readily and accurately adjustable to permit the grind- 7 ing ofvarious work diameters within an extended range and which isparticularly well suited to the precision grinding of extremely smallparts of all kinds.

A further object of the invention is to design a centerless grindingattachment which may be simply and readily adjusted to govern the rateat which the work passes between the grinding and regulatory wheels.

Another object of the invention is to provide a centerless grindingattachment capable of high speed production operations which can bedriven from the head stock of conventional center-type externalgrinders.

A still further object of the invention is to provide an attachment ofthe type described which when incorporated with a conventional grindingmachine, increases its speed of operation and rate of production.

A still further object of the invention is to design a centerlessgrinding attachment which can be very quickly mounted on a grindingmachine and removed therefrom,

and which can be very rapidly set in position, thus per mitting a changeof grinding wheels or a change in position to grind work of a differentsize with a minimum of down time.

With the above and other objects in view, the present invention consistsin the combination and arrangement of-parts, hereinafter more fullydescribed, illustrated in the accompanying drawing, and moreparticularly pointed out in the appended claims, it being understoodthat changes may be made in the form, size, proportion, and minordetails of construction, without departing from the spirit, orsacrificing any of the advantages of the invention.

in the drawing:

Fig. 1 is an end elevational view of my grinding attachment mounted on aconventional external grinding machine, fragmentary portions of thegrinding wheel and bed of the machine only being shown.

Fig. 2 is a top plan view thereof showing also the centers and spindleof the grinding machine.

Fig. 3 is an end elevational view of the adjustable work support memberonly.

Fig. 4 is a reduced sectional view through the regulating wheel whichforms a portion of my novel attachment.

at variable speeds in a clockwise direction as usual so that the speedof the regulating wheel 12 can be varied to suit the operation.

Slidably supported on the ways 10 is a carriage 24 which is providedwith guides 25, and it will be seen that a transversely disposed worksupporting member 26 is adjustably mounted on the carriage 24, slots 27in one end of the member 26 accommodating bolts 28 on the carrier 24which can be tightened down to clamp the member 26 in adjusted position.The opposite end of the member 26 is recessed as at 29 to accommodatethe peripheral edge of the grinding wheel 11 which extends therein, andsupport blocks 30 are provided adjacent the sides of the recess asshown.

The work W which is fed between the wheels 11 and 12 in any suitablemanner is peripherally supported on a tilted work rest blade 31 whichincludes an inclined supporting surface with a carbide tipped edge.Fixed to the blade 31 are laterally extending bolts 33 which areadjustably accommodated in the slots 34 provided in the blocks 30, andit will be clear that the blade 31 can be clamped in position bytightening down of the nuts 35 I on the ends of the bolts 33.

In operation, both the regulating wheel 12 and the grinding wheel 11 aredriven in a clockwise direction, the peripheral speed of the wheel 12being slightly in excess of the peripheral speed of the Wheel 11 so thatthe wheel 12 in frictionally engaging the work and retaining it incontact with the wheel 11 controls its rotation andeliminates chatterand slippage.

The work W can be fed from either direction and in the instantapplication is fed to the left end of the blade 31 (see Fig. 3) by handor by employment of a chute or other feed mechanism (not shown), and itwill be observed that the blade 31 is tilted so that the work feeds fromleft to right, and finally is discharged into a suitable receptacle (notshown) adjacent the right end of the blade. The rate of feed of the workis controlled by variation of the tilt of the blade 31 and variation ofthe speed of travel of the regulating wheel 12.

The device can be readily adjusted to grind cylindrical work toextremely fine tolerances by setting of the grinding wheel 11 relativeto the axis of the regulating wheel 12, so that the minimum distancebetween their opposed peripheral surfaces is slightly less than thediameter to the ground; then by approximate setting of the position ofthe support member 26 relative to the wheels 11 and 12, and finally byadjustment of the vertical position of the blade 13 relative to theslots 34 and variance of the position of the grinding wheel 11 until thecorrect position of these elements is determined. Sincethe heads of thebolts 33 for clamping the blade 31 in position are located on the faceof the blocks 30 remote from the regulating wheel 12, it will be clearthat they are readily accessible to the operator for setting theposition of the blade 31. Further, since the slots 34 are open to thetops of the blocks 30, it will be apparent that a replacement blade 31can be readily substituted for one which has become worn withoutdisturbing the adjusted position of the other elements.

Thus, for high speed grinding of cylindrical work surfaces to extremelyclose tolerances, it will be apparent that by employing the novelattachment which I have perfected, I can adapt a conventional, centertype external grinding machine so that production centerless grindingoperations can be performed thereon. The difierence in the cost ofproviding such attachments in lieu of purchasing a cen terless grindingmachine will be readily appreciated.

By provision of an individual motor drive for the regulating wheel, italso will be possible to employ the attachment with surface and cuttergrinders. It is to be understood that the carriage 24 for the support,member can be modified or eliminated if necessary to adapt to varioustypes of external grinders and that various equivalent changes may bemade in the various elements of the device without departing from thespirit of the invention or the scope of the subjoined claims.

What I claim is:

1. In an attachment for an external grinding machine. including agrinding wheel adapted to be driven in a predetermined direction, andhaving center means, including a live center, in axial parallelism withthe axis of the grinding wheel and rearward thereof; a plate forrelative movement with the periphery of said wheel provided for mountingon said machine; means for securing said last mentioned plate inposition; a regulating wheel for mounting in axially parallel relationwith said grinding wheel a spaced distance rearward therefrom on saidcenters; said regulating wheel being at least twice the width of thegrinding wheel and extending axially beyond said grinding wheel on atleast one side thereof a predetermined distance greater than the widthof the grinding wheel; the front of said plate extending under saidregulating wheel; blocks on said plate on either side of the grindingwheel opposite the side faces thereof with rear faces in near alignmentwith the periphery of the grinding wheel; a work supporting blade,having an inclined face adjacent the regulating wheel, of. at leasttwice the Width. of the grinding wheel; said blade being mounted on thesaid faces of said blocks between said regulatory wheel and, grindingwheel and extending beyond said grindingwheel; on at leastone sidethereof opposite the extending side of the regulating wheel so as to bedisposed opposite said blocks and wheel to provide, with said wheel,work feeding surfaces on which a workpiece is revolved prior to reachingsaid grinding wheel by the regulating wheel, and clamping means tosecure the blade to said blocks.

2. The combination defined in claim 1 in which lateral openings parallelto the grinding wheel are provided through said blocks and posts extendfrom said blade through said openings in a manner so as not to projectoutward of the rear faces of said blocks and securing means on the endsof the posts clamping said blade to the blocks.

3. In combination with an external grinding machine including a grindingwheel adapted to be driven in a predetermined direction, a worksupporting surface rearward of the wheel and opposite the peripheraledge of the wheel, means mounted on said work supporting surfaceincluding a guide plate having guides formed thereon movable withrelation to said support surface toward and away from the periphery ofsaid grinding wheel, means securing said guide plate in positionrelative to said support surface, a regulating wheel mounted in axiallyparallel relation with said grinding wheel a spaced distance therefrom,means supporting and driving the regulating wheel, said regulating wheelextending substantially beyond said grinding wheel on both sidesthereof, the front of said guide plate extending under said regulatingwheel and being recessed to receive the edge of said grinding wheel, anupstanding block on the front of said guide plate on each side of thegrinding wheel having a lateral slot therethrough open to the top facethereof. the blocks having rear faces substantially aligned with theperipheral edge of the grinding wheel, a tilted work support bladehaving an upper surface sloping upwardly away from said regulating wheelmounted directly on the rear faces of said blocks adjacent theregulating wheel, said regulating Wheel being of sufi'icient length toextend out from said grinding wheel opposite said blocks and blade toprovide surface for feeding the workpiece to the grinding wheel andrevolving it prior to the time it reaches the grinding Wheel, threadedmeans extending laterally from the front face of the blade forwardlythrough the slots in the blocks, and clamping means thereon. forwardlyof the blocks to secure the blade in adjusted position.

References Cited in the file of this patent UNITED STATES PATENTS1,456,462 Reeves; May 22, 1923 11,579,934 Heim Apr. 6, 1926 1,585,983Heim May 25, I926 1,733,087 Heim Oct. 22, 1929 1,737,852 Kern Dec. 3,1929 1,814,431. Caster July 14, 1931 1,987,850, Heim Jan. 15, 19352,,l5l,365 Winkler Mar. 21, 1939 2,375,396 K'aplin May 8, 1945 2,559,430I-Iollengreen et a1. July 3, 1951 FOREIGN PATENTS 306,177 Great BritainFeb. 18, 1929

